Purpose : We aimed to evaluate the impact of a exercise with kinect-based mixed reality device (KMR) on physical function, upper extremity disability, fatigue, and quality of life in breast cancer survivors. We hypothesized that this exercise program would improve physical function, physical activity, fatigue, and quality of life. Methods : Thirty-nine breast cancer survivors were randomized to either the KMR exercise group (KE) or the home stretch group (HS). The KE participated in 8 weeks of exercise, exercising 3 times per week, while the HS performed 8 weeks of stretching exercises, also 3 times per week. Before and after the intervention period, participants underwent assessments of physical function, including body composition, chester step test (CST), and hand grip strength (HGS). Additionally, participants completed questionnaires including the international physical activity questionnaire (IPAQ), disabilities of the arm, shoulder and hand (DASH) questionnaire, and functional assessment of cancer therapy-breast (FACT-B) questionnaire to measure their physical activity levels, upper extremity disability, and quality of life, respectively. Results : Overall, significant improvements were observed in several shoulder movements, body weight, and physical activity, with no significant interaction effects between groups and time. Furthermore, there was a significant group by time interaction for body weight, left flexion, right flexion, right abduction, and left adduction, as well as for upper extremity disability (K-DASH) and quality of life (FACT-B). Conclusion : In conclusion, the KMR exercise program was found to be effective at improving physical function, upper extremity disability, quality of life, and overall well-being in breast cancer survivors. The significant improvements observed in multiple measures and the significant group by time interactions for various outcomes highlight the potential benefits of this KMR exercise program in promoting a better quality of life for breast cancer survivors.